Diffuse Surface Scattering and Quantum Size Effects in the Surface Plasmon Resonances of Low-Carrier-Density Nanocrystals

The detailed understanding of the physical parameters that determine localized surface plasmon resonances (LSPRs) is essential to develop new applications for plasmonics. A relatively new area of research has been opened by the identification of LSPRs in low-carrier-density systems obtained by doping semiconductor quantum dots. We investigate theoretically how diffuse surface scattering of electrons in combination with the effect of quantization due to size (QSE) impact the evolution of the LSPRs with the size of these nanosystems. Two key parameters are the length R0 giving the strength of the QSE and the velocity βT of the electronic excitations entering in the length scale for diffuse surface scattering. Although the QSE itself only produces a blueshift in energy of the LSPRs, the diffuse surface scattering mechanism gives to both energy and line width an oscillatory-damped behavior as a function of size, with characteristic lengths that depend on material parameters. Thus, the evolution of the LSPRs w...